Book mostly about the alien and sedition acts of 1798, which motivated by fear of French threats to national security and desire to protect the young Republic, made immigration harder, made deportation easier, and criminalized anything said or printed hostile to government that might not be accurate.
Federalists argued that although the 1st amendment protected free speech, you have to protect government as a foundation for that amendment. Although it appears only a handful were jailed and fined, public sympathies with these martyrs of freedom helped push the Federalists from power in 1800. Eventually the party dissolved completely.
Today, the desire to use government as a tool for speech justice lies in opposing Islamic extremism on the right and preventing speech degrading to racial and sexual minorities on the left. Although not mentioned in the book, citizens are of course also not free to talk about information deemed classified by the government.